In 1959 Armen completed his studies at Kooshesh Davtian School, Tehran. In 1969 he earned his doctorate in architecture from the Department of Architecture of the Faculty of Architecture and Civil Engineering at RWTH Aachen University of Aachen. In 1973 he graduated from the Department of Urban Planning of the same faculty having earned another doctorate in technical sciences (Doktor der Ingenieurwissenschaften) as an architect-planner.

A. Hakhnazarian started his research activities in 1968, when he embarked on measuring St. Thaddeus Monastery in Artaz District (at present: Maku in West Azerbaijan Province, Iran).
In the 1970s, A. Hakhnazarian made six research trips to Western Armenia (at present: Eastern Turkey), each lasting for almost two months.
Later, however, he was declared persona non grata and banned from participating in future research trips in Western Armenia. Nevertheless, he continued his studies by sending other researchers to Western Armenia, Armenia Minor and Cilicia up until his untimely death.

In 1973 A. Hakhnazarian married architect Margrit Buenemann. They have two daughters: Talin and Shahriz.
In 1974 he founded and headed Monit Architectural Company in Tehran, Iran.
In 1982 A. Hakhnazarian officially established Research on Armenian Architecture (RAA) NGO (Foundation since 2010) in Aachen, Germany. In 1996 it was registered in the United States, and in 1998 in Armenia.
In 1983 A. Hakhnazarian started teaching in the Faculty of Urban Planning at Aachen University, Germany, his lecturer’s career lasting for many years.
A. Hakhnazarian died in Aachen, part of his ashes being buried there and the rest in the cemetery of Artashavan Village, Aragatzotn Region, Armenia.